Lead-acid battery formulations containing discrete carbon nanotubes

ABSTRACT

Compositions of discrete carbon nanotubes for improved performance lead acid batteries. Further disclosed is a method to form a lead-acid battery with discrete carbon nanotubes.

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 61/500,561, entitled “LEAD-ACID BATTERY FORMULATIONS COMPRISINGDISCRETE CARBON NANOTUBE FIBERS,” filed on Jun. 23, 2011, and to U.S.Provisional Patent Application Ser. No. 61/638,454, entitled “LEAD-ACIDBATTERY FORMULATIONS COMPRISING DISCRETE CARBON NANOTUBE FIBERS,” filedon Apr. 25, 2012, the entire content of each of which is herebyincorporated by reference.

FIELD OF THE INVENTION

The present invention is directed to novel compositions and methods forproducing a lead-acid battery with discrete carbon nanotubes or mixturesof discrete carbon nanotubes and plates of graphene or oxidizedgraphene.

BACKGROUND

Carbon nanotubes can be classified by the number of walls in the tube,single-wall, double wall and multiwall. Each wall of a carbon nanotubecan be further classified into chiral or non-chiral forms. Carbonnanotubes are currently manufactured as agglomerated nanotube balls orbundles. Use of carbon nanotubes and graphene as enhanced performanceadditives in batteries is predicted to have significant utility forelectric vehicles, and electrical storage in general. However,utilization of carbon nanotubes in these applications is hampered due tothe general inability to reliably produce individualized carbonnanotubes.

The performance goals of a lead-acid battery are to maximize thespecific power (power per unit of weight, measured in watts perkilogram) over designated high rate discharge scenarios, and maximizebattery life, not only in environmental durability but also mostimportantly in cycle life (number of possible charges and discharges).

Both corrosion (on the positive plate) and sulfation (on the negativeplate) define two key failure modes of today's lead acid batteries.Regarding corrosion failures, this failure mode begins to accelerateeither as temperatures rise about 70° F. and/or if the battery is leftdischarged. To mitigate the effects of the corrosion process, mostbattery companies focus their research on developing more corrosionresistant lead-alloys and grid manufacturing processes that reduce themechanical stresses in the as-manufactured grids. Regardless of thealloy or grid fabrication process, essentially all battery manufacturersengineer battery service life based on lead alloy and grid wirecross-sectional area. Normally this engineering translates as a changein grid thickness and corresponding plate thickness. Thicker gridsprovide longer life, but usually sacrifice power density, cost, weight,and volume.

Regarding sulfation failures, when a lead acid battery is left on opencircuit stand, or kept in a partially, or fully discharged state for aperiod of time, the lead sulfate formed in the discharge reactionrecrystallizes to form larger, low surface area lead sulfate crystalswhich are often referred to as hard lead sulfate. This low surface area,non-conductive lead sulfate, blocks the conductive path needed forrecharging. These crystals, especially those furthest removed from theelectrode grid, are difficult to convert back into the charged lead andlead dioxide active materials. Even a well maintained battery will losesome capacity over time due to the continued growth of large leadsulfate crystals that are not entirely recharged during each recharge.These sulfate crystals, of density 6.287 g/cc, are also larger in volumeby about 37% than the original paste, so they mechanically deform theplate and push material apart. The resulting expansion and deformationof the plates also causes active material to separate from theelectrodes with a commensurate loss of performance. Sulfation is themain problem in recreational applications during battery storage whenthe season ends. Boats, motorcycles, snowmobiles lie dormant in theiroff-use months and, left uncharged, discharge toward a zero %state-of-charge, leading to progressive sulfation of the battery. Thus,the battery cannot be recharged anymore, is irreversibly damaged, andmust be replaced.

As users have come to know portable battery products in cell phones andlaptop computers, they have correspondingly become comfortable with theprocess of bringing a battery down to almost no charge and then bringingit back to full, complete charge and power capabilities within hours.Traditional lead-acid batteries, because of their inherent design andactive material utilization limitations, only provide relatively goodcycle-life when less than about 80% of the rated capacity is removedduring each discharge event in an application. A battery of this typesuffers a significant decrease in the number of times it can bedischarged and recharged, i.e., cycle life, when 100% of the ratedcapacity is consumed during a single discharge in an application. Manynew products that historically used lead-acid batteries are requiring asignificant jump in cycle life. The most notable examples are HybridElectric Vehicles, which operate in a High Rate Partial-State-of-Chargecondition. This is a punishing application which dramatically shortensthe cycle life of a typical lead acid battery, and has therefore leftcar companies with no choice, but to go to much more expensiveNickel-Metal Hydride batteries, and experiment with Lithium ionbatteries.

Typically, a lead-acid battery will require a recharge timesignificantly longer than competitive batteries containing advancedmaterials seen in portable products. A complete charging of a lead-acidbattery, such as found in electric vehicles, can take from 8 to 16hours. In the case of Uninterrupted Power Supplies (UPS), a rapid chargerate is essential to ensuring quality performance, as well as reducingthe related capital expenditures for back up equipment while chargingtakes place on initial batteries put into service.

Environmental conditions such as vibration can also result indegradation of a lead-acid battery due to active material separatingfrom the cathode or anode. More vibration-resistant batteries, such asused for pleasure boats, often contain thicker electrodes or specialvibration damping structures within the battery. This increases theweight and cost of the battery. Hence, an increased mechanical strengthof the active material paste would be a highly desirable feature.

Traditional methods for producing battery plates for lead-acid batteriesgenerally involve a mixing, curing and drying operation in which theactive materials in the battery paste undergo chemical and physicalchanges that are used to establish the chemical and physical structureand subsequent mechanical strength necessary to form the battery plate.To produce typical battery plates, materials are added to commercialpaste mixing machines common in the industry in the order of lead oxide,flock, water and sulfuric acid, which are then mixed to a pasteconsistency. The flock component is a fibrous material, usually composedof polyester, nylon or acrylic fibers, which is added optionally to thepaste to increase the mechanical strength of the pasted plate. An“expander” component is conventionally added to the negative pasteconsisting of a mixture of barium sulfate, carbon black andlignosulfonate that is added to the negative paste to improve theperformance and cycle lifetime of the battery. During mixing, chemicalreactions take place in the paste producing basic lead sulfates, themost common of which is tribasic lead sulfate. The final pastecomposition is a mixture of basic lead sulfates, unreacted lead monoxideand residual free lead particles. Pasting is the process of making abattery plate. This paste is dispersed into a commercial automaticpasting machine of a type common in the industry, which applies thepaste to a grid structure composed of a lead alloy at high speed. Thepaste plates are generally surface dried in a tunnel dryer of a typecommon in the industry and then either stacked in columns or placed onracks. The stacked or racked plates are then placed in curing chambers.It is very important during the entire pasting and curing operation thatthe paste has sufficient mechanical strength to avoid micro-crackformation and hence increased internal electrical resistance from thepaste mix. A high internal electrical resistance can limit rates ofdischarge and charging as well as result in localized heating duringcharging/discharging and increased chemical degradation of the activespecies.

In efforts to reduce the high impedance of the battery to accelerate theformation (first charging) step, carbon black has been added to thepaste. However, to properly disperse the carbon black surfactants areemployed, but these surfactants create higher impedance that isdifficult for the carbon black particles to reduce. Also, because thereis often a region of high impedance due to the non-homogeneous contactresistance of the powders there is often applied an overvoltage whichresults in electrolysis of water, generating oxygen at the cathode whichthen rapidly degrades the carbon black. It is highly desirable to have ameans to lower impedance in lead-acid batteries that can avoidovervoltage requirements for charging as well as a longer lastingconducting additive for the cathode.

SUMMARY

The present invention relates to lead-acid battery comprising of aplurality of discrete carbon nanotube fibers having an aspect ratio offrom about 10 to about 500 and optionally wherein the discrete carbonnanotubes are open ended. The carbon nanotube fibers can comprise anoxidation level from about 1 weight percent to about 15 weight percent.The mixture of the plurality of discrete carbon nanotubes can compriseat least one surfactant or dispersing aid, which contains a sulfatemoiety. The composition of oxidized and discrete carbon nanotubes can bedispersed in water to make the expander material and/or the batterypaste.

A further aspect of this invention is a material for a battery paste fora lead-acid battery comprising a plurality of discrete carbon nanotubeshaving an aspect ratio of from about 10 to about 500, preferably fromabout 25 to about 250, an organic material, and optionally at least oneinorganic salt, such as barium sulfate, tetra-basic lead sulfate,calcium sulfate or tin oxide, and optionally at least one non-fibercarbon moiety, such as graphite, graphene, graphene plates,functionalized graphene, oxidized or oxygenated graphene, or carbonblack. The organic material may comprise a sulfonated polymer,preferably one selected from the group consisting of sulfonated polymersincluding but not limited to, lignosulfonate, sulfonated polystyrene orcombinations of sulfonated polymers thereof.

Another aspect of this invention is a process to form a lead-acidbattery comprising the steps of a) selecting discrete carbon nanotubefibers having an aspect ratio of from about 10 to 500, b) selectingdiscrete carbon nanotube fibers having an oxidation level from 1-15% byweight, c) selecting discrete carbon nanotubes having at least a portionof open-ended tubes, d) blending the fibers with a liquid to form aliquid/fiber mixture, d) optionally combining the liquid/fiber mixturewith a sulfonated polymer, f) optionally adjusting the pH to a desiredlevel, g) optionally combining the liquid/fiber mixture with at leastone surfactant, h) agitating the liquid/fiber mixture to a degreesufficient to disperse the fibers to form a liquid/dispersed fibermixture, i) optionally combining the liquid/dispersed fiber mixture withat least one inorganic salt, j) optionally combining at least onenon-fiber carbon moiety, k) optionally drying the dispersed fibermixture, and l) combining the dispersed carbon nanotube fiber/compositemixture with the lead containing components to form a battery paste mix.The agitation step h) preferably is with sonication.

A further aspect of this invention is the carbon nanotube fibers can becombined or coated with at least one conductive polymer, preferably oneselected from the group consisting of polyaniline, polyphylene vinylene,polyvinylpyrollidone, polyacetylene, polythiophene, polyphenylenesulfide, their blends, copolymers, and derivatives thereof.

One embodiment of this invention is a battery that has at least onelayer comprising discrete carbon nanotube fibers.

Another embodiment of this invention is a battery paste comprisingdiscrete carbon nanotubes that exhibits at least 10% improved adhesionto the electrodes such as carbon/lead and other lead or carbon typeelectrodes than those pastes without carbon nanotubes.

Yet another embodiment of this invention is a battery comprisingdiscrete carbon nanotubes that exhibits at least 10% increase in iontransport at any temperature for a given electrolyte concentrationcompared to those batteries without carbon nanotubes at the sameelectrolyte concentration and temperature.

A further embodiment of this invention is a negative electrode for anenergy storage device, comprising: a current collector; acorrosion-resistant conductive coating secured to at least one face ofthe current collector; a sheet comprising carbon particles and carbonnanotube fibers comprising 1-15 percent weight oxidized species and ofaspect ratio of from about 10 to about 500, said sheet adhered to thecorrosion-resistant conductive coating; a tab portion extending from aside of said negative electrode; optionally a lug comprising a lead orlead alloy that encapsulates the tab portion; and a optionally a cast-onstrap comprising lead or lead alloy above the lug and encapsulating atleast part of the lug.

Another aspect of this invention is a lead-acid battery wherein at leastone of the electrode battery pastes has a gradient of concentration ofdiscrete carbon nanotubes through the thickness of the paste, optionallyhaving the highest concentration of the material at the surface of thecurrent collector or at the surface of the separator.

A further aspect of this invention is a lead-acid battery of comprisingdiscrete carbon nanotubes useful for vehicles equipped with energyregenerative braking systems or start-stop technology for improved fuelefficiency. Also they can be useful for uninterrupted power supplies andpower smoothing.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a charge profile at constant amperage for a lead acidbattery with carbon nanotubes according to the present invention(Example 3), and without carbon nanotubes according to the presentinvention (Control 3);

FIG. 2 shows a charge profile at constant voltage for a lead acidbattery with carbon nanotubes according to the present invention(Example 3), and without carbon nanotubes according to the presentinvention (Control 3).

FIG. 3 shows an electron micrograph of the dried anode material ofexample 3 after 14 charging and discharging cycles.

FIG. 4 shows an electron micrograph of the dried cathode material ofexample 3 after 14 charging and discharging cycles.

DETAILED DESCRIPTION

In the following description, certain details are set forth such asspecific quantities, sizes, etc., so as to provide a thoroughunderstanding of the present embodiments disclosed herein. However, itwill be evident to those of ordinary skill in the art that the presentdisclosure may be practiced without such specific details. In manycases, details concerning such considerations and the like have beenomitted inasmuch as such details are not necessary to obtain a completeunderstanding of the present disclosure and are within the skills ofpersons of ordinary skill in the relevant art.

While most of the terms used herein will be recognizable to those ofordinary skill in the art, it should be understood, however, that whennot explicitly defined, terms should be interpreted as adopting ameaning presently accepted by those of ordinary skill in the art. Incases where the construction of a term would render it meaningless oressentially meaningless, the definition should be taken from Webster'sDictionary, 3rd Edition, 2009. Definitions and/or interpretations shouldnot be incorporated from other patent applications, patents, orpublications, related or not, unless specifically stated in thisspecification or if the incorporation is necessary for maintainingvalidity. Aspect ratio is the ratio of length divided by diameter (L/D)where the selected units for length and diameter are the same, thuscanceling the units when ratioed, making the aspect ratio a unitlessnumber.

For an automotive positive plate paste mix, the specific gravity of thesulfuric acid in the mixture examples is preferably approximately 1.400and the paste density is typically in the range of approximately4.15-4.27 g/cc. For the automotive negative plate paste mix, thespecific gravity of the sulfuric acid is preferably approximately 1.400and the paste density is typically in the range of approximately4.27-4.39 g/cc. For the industrial positive plate paste mix, thespecific gravity of the sulfuric acid is preferably approximately 1.400and the paste density is typically in the range of approximately4.33-4.45 g/cc. For the industrial negative plate paste mix the specificgravity of the sulfuric acid is preferably approximately 1.400 and thepaste density is typically in the range of approximately 4.45-4.57 g/cc.The paste density is a measure of the composition of the paste and alsoof its suitability for being pasted by commercial paste mixing machines.The “flock” component is a fibrous material, usually composed ofpolyester, nylon or acrylic fibers, which is added optionally to thepaste to increase the mechanical strength of the pasted plate. The“expander” component is conventionally a mixture of barium sulfate,carbon black and lignosulfonate that is added to the negative paste toimprove the performance and life of the negative plate.

In various embodiments, a plurality of carbon nanotubes is disclosedcomprising single wall, double wall or multi wall carbon nanotube fibershaving an aspect ratio of from about 10 to about 500, preferably fromabout 60 to about 200, and a oxidation level of from about 1 weightpercent to about 15 weight percent, preferably from about 2 weightpercent to about 10 weight percent. The oxidation level is defined asthe amount by weight of oxygenated species covalently bound to thecarbon nanotube. The thermogravimetric method for the determination ofthe percent weight of oxygenated species on the carbon nanotube involvestaking about 5 mg of the dried oxidized carbon nanotube and heating at5° C./minute from room temperature to 1000 degrees centigrade in a drynitrogen atmosphere. The percentage weight loss from 200 to 600 degreescentigrade is taken as the percent weight loss of oxygenated species.The oxygenated species can also be quantified using fourier transforminfra-red spectroscopy, FTIR, particularly in the wavelength range1730-1680 cm⁻¹, or by using energy dispersive x-ray measurements.

The carbon nanotube fibers can have oxidation species comprising ofcarboxylic acid or derivative carbonyl containing species and areessentially discrete individual fibers, not entangled as a mass. Thederivative carbonyl species can include ketones, quaternary amines,amides, esters, acyl halogens, monovalent metal salts and the like.

An illustrative process for producing discrete oxidized carbon nanotubesfollows: 3 liters of sulfuric acid, 97 percent sulfuric acid and 3percent water, and 1 liter of concentrated nitric acid containing 70percent nitric acid and 3 percent water, are added into a 10 litertemperature controlled reaction vessel fitted with a sonicator andstirrer. 40 grams of non-discrete carbon nanotubes, grade Flowtube 9000from CNano corporation, are loaded into the reactor vessel whilestirring the acid mixture and the temperature maintained at 30° C. Thesonicator power is set at 130-150 watts and the reaction is continuedfor three hours. After 3 hours the viscous solution is transferred to afilter with a 5 micron filter mesh and much of the acid mixture removedby filtering using a 100 psi pressure. The filter cake is washed onetimes with about four liters of deionized water followed by one wash offour liters of an ammonium hydroxide solution at pH greater than 9 andthen about two more washes with four liters of deionized water. Theresultant pH of the final wash is 4.5. A small sample of the filter cakeis dried in vacuum at 100° C. for four hours and a thermogravimetricanalysis taken as described previously. The amount of oxidized specieson the fiber is 8 percent weight and the average aspect ratio asdetermined by scanning electron microscopy to be 60.

The discrete oxidized carbon nanotubes (CNT) in wet form are added towater to form a concentration by weight of 1 percent and the pH isadjusted to 9 using ammonium hydroxide. Sodium dodecylbenzene sulfonicacid and is added at a concentration 1.5 times the mass of oxidizedcarbon nanotubes. The solution is sonicated while stirring until the CNTare fully dispersed in the solution. Sufficient dispersion of individualtubes is defined when the UV absorption at 500 nm is above 1.2absorption units for a concentration of 2.5×10⁻⁵ g CNT/ml.

An illustrative process for producing discrete carbon nanotube/graphenecompositions follows: 3 liters of sulfuric acid, 97% sulfuric acid and3% water, and 1 liter of concentrated nitric acid containing 70% nitricacid and 30% water, are added into a 10 liter temperature controlledreaction vessel fitted with a sonicator and stirrer. 20 grams ofnon-discrete carbon nanotubes, grade Flowtube 9000 from CNanoCorporation, and 20 grams of expanded graphite obtained from RiceUniversity, Houston, Tex., USA are loaded into the reactor vessel whilestirring the acid mixture and the temperature maintained at 25° C. Thesonicator power is set at 130-150 watts and the reaction is continuedfor 3 hours. After 3 hours the viscous solution is transferred to afilter with a 5 micron filter mesh and much of the acid mixture removedby filtering using about 100 psi pressure. The filter cake is washed 1times with 4 liters of deionized water followed by 1 wash of 4 liters ofan ammonium hydroxide solution at pH>9 and then two or more washes with4 liters of deionized water. The resultant pH of the final wash is >4.5.An electron micrograph will show graphene plates interspersed carbonnanotubes.

Cathode, or Negative Active Material, Paste

Control 1. 79.3 grams of Massicot (lead(II) oxide), is mixed with 0.634grams of sodium sulfate and 0.793 grams of expander material (Hammond,grade 631). 9.28 grams of water is combined with a 0.397 grams of Teflonemulsion (Du Pont, grade K20) and added to the Massicot containingmixture. 17.08 grams of sulfuric acid, specific gravity 1.4, is thenslowly added while mixing, and maintaining the temperature between 49and 54 degrees centigrade. The mixture is mixed thoroughly. The densityof the paste is 63.2 g/inch cubed.

EXAMPLE 1

The negative active paste material is made as control 1 except that theexpander material contains discrete carbon nanotubes which is made asfollows. 10 grams of Hammond expander 631 which contains lignosulfonate,barium sulfate and carbon black, is added to 200 cc of deionized water.0.25 grams of carbon nanotubes oxidized to approximately 6% by weight,is added followed by sonication in a sonicator bath for 30 minutes. Themixture containing the carbon nanotubes is then dried to give a freeflowing powder.

Anode, or Positive Active Material, Paste

Control 2. 75.7 grams of Red lead (lead(III) tetroxide), is mixed with0.6056 grams of sodium sulfate. 14.83 grams of water is combined with a0.389 grams of Teflon emulsion (Du Pont, grade K20) and added to theMassicot containing mixture. 15 grams of sulfuric acid, specific gravity1.4, is then slowly added while mixing, and maintaining the temperaturebetween 49 and 54 degrees centigrade. The mixture is mixed thoroughly.The density of the paste is 60.78 g/inch cubed.

EXAMPLE 2

A single battery cell is constructed by evenly coating lead cathode andanode film with negative and positive paste, respectively, interspersinga glass fiber matt, then filling with sulfuric acid of specific gravity1.12. The negative paste has 0.05% weight carbon nanotubes relative tothe starting lead oxide.

Control 3. A single battery cell is constructed by evenly coating leadcathode and anode film with negative and positive paste, respectively,interspersing a glass fiber matt, then filling with sulfuric acid ofspecific gravity 1.12. The negative paste contains no carbon nanotubes.

The cell of control 3 is determined to have an internal resistance of100 ohms. The cell of example 2 containing the discrete carbon nanotubesis determined to have an internal resistance of 50 ohms.

EXAMPLE 3

A single battery cell is constructed by evenly coating lead cathode andanode film with negative and positive paste, respectively, interspersinga glass fiber matt, then filling with sulfuric acid of specific gravity1.12. The positive and negative paste has 0.16% weight carbon nanotubesrelative to the starting lead oxide. The pastes of Example 3 areobserved to be more easily handled and transferred to the lead currentcollector plates without breakage than Control 3.

Shown in FIG. 1 is a typical current limiting first charge cycle forcontrol 3 and Example 3. Although in each case the current profile isthe same, the voltage for the Example 3 is lower, exemplifying thatExample 3 with carbon nanotubes of this invention has a lower impedancethan control 3. Furthermore, overvoltage which produces electrolysis ofthe water is avoided in example 3 compared to Control 3. Also seen inFIG. 1 on discharging at a rate that would fully discharge the batteryin 3 hours, the Example is seen to exhibit the benefits of a lowervoltage but higher current compared to the control.

Shown in FIG. 2 is the result of charging Example 3 and Control 3 at aconstant voltage in two steps. After 2 hours the voltage was raised to2.3 volts. Example 3 is able to absorb a much higher current thanControl 3 and could be fully charged. On discharging, Example 3 gave anexpected discharge profile whereas the Control 3 had deemed to havefailed. The results of Example 3 are considered to be consistent withthe paste having a much enhanced and more uniform conductivity.

Shown in FIG. 3 is an electron micrograph of the dried anode material ofExample 3 after 14 charges and discharges. On the 14^(th) discharge itwas discharged to 1.75 volts, i.e. not fully discharged, therefore twocrystal types are present, lead and lead sulfate, as illustrated in FIG.3. The carbon nanotubes of this invention are seen to be very wellinterspersed between the lead particles. The lead sulfate crystals areseen to incorporate the carbon nanotubes of this invention.

Shown in FIG. 4 is an electron micrograph of the dried cathode materialof Example 3 after 14 charges and discharges. On the 14^(th) dischargeit was discharged to 1.75 volts, i.e. not fully discharged, thereforetwo crystal types are present, lead dioxide and lead sulfate, asillustrated in FIG. 4. The carbon nanotubes of this invention are seento be incorporated within the lead dioxide and lead sulfate crystals.This illustrates that the carbon surfaces are protected by the leaddioxide or lead sulfate and so would be expected to be less prone tooxidative attack if electrolysis occurs by over voltage.

The invention claimed is:
 1. A lead-acid battery paste, comprising abattery blend prepared from a battery mixture comprising: lead oxide; aplurality of discrete individual carbon nanotube fibers, not entangledas a mass, having an aspect ratio of from about 10 to about 500; anorganic material; an inorganic salt; and a non-fiber carbon moiety,wherein the discrete carbon nanotube fibers have an oxidation level fromabout 1 weight percent to about 15 weight percent.
 2. The batterymixture of claim 1, wherein the inorganic salt is selected from thegroup consisting of: barium sulfate, lead sulfate, calcium sulfate, tinoxide, and mixture thereof.
 3. The battery mixture of claim 1, whereinthe non-fiber carbon moiety is selected from the group consisting of:carbon black, graphite, graphene, and mixture thereof.
 4. A lead-acidbattery paste comprising a battery blend prepared from a battery mixturecomprising: lead oxide; a plurality of discrete individual carbonnanotube fibers, not entangled as a mass, having an aspect ratio of fromabout 10 to about 500; and an organic material, wherein the discretecarbon nanotube fibers have an oxidation level from about 1 weightpercent to about 15 weight percent.
 5. The battery mixture of claim 1,wherein the discrete carbon nanotube fibers are coated with a conductivepolymer.
 6. The battery mixture of claim 4, wherein the discrete carbonnanotube fibers are coated with a conductive polymer.
 7. The batterymixture of claim 5, wherein the conducting polymer is selected from thegroup consisting of: polyaniline, polyphenylene vinylene,polyvinylpyrollidone, polyacetylene polythiophene, polyphenylenesulfide, and blends, copolymers, and derivatives thereof.
 8. The batterymixture of claim 6, wherein the conducting polymer is selected from thegroup consisting of: polyaniline, polyphenylene vinylene,polyvinylpyrollidone, polyacetylene polythiophene, polyphenylenesulfide, and blends, copolymers, and derivatives thereof.
 9. The batterymixture of claim 1, further comprises at least one surfactant ordispersing aid.
 10. The battery mixture of claim 4, further comprises atleast one surfactant or dispersing aid.
 11. The battery mixture of claim9, wherein the surfactant or dispersing aid is a sulfonated polymerselected from the group consisting of: ligno-sulfonate, sulfonatedpolystyrene, and combinations thereof.
 12. The battery mixture of claim10, wherein the surfactant or dispersing aid is a sulfonated polymerselected from the group consisting of: ligno-sulfonate, sulfonatedpolystyrene, and combinations thereof.
 13. The battery mixture of claim1, further comprising water, wherein the discrete carbon nanotube fibersare dispersed in the water.
 14. The battery mixture of claim 4, furthercomprising water, wherein the discrete carbon nanotube fibers aredispersed in the water.
 15. The lead-acid battery paste of claim 1,wherein the lead-acid battery paste has a concentration gradient throughthe thickness of the acid-battery battery paste.
 16. The lead-acidbattery blend of claim 4, wherein the lead-acid battery paste has aconcentration gradient through the thickness of the battery paste. 17.The lead-acid battery paste of claim 1, wherein the lead-acid batterypaste has a highest concentration at a surface of a current collector orat a surface of a separator.
 18. The lead-acid battery paste of claim 4,wherein the lead-acid battery paste has a highest concentration at asurface of a current collector or at a surface of a separator.
 19. Thebattery mixture of claim 1, wherein the carbon nanotubes comprise atleast about 70 percent, by weight, of discrete carbon nanotubes.
 20. Thebattery mixture of claim 4, wherein the carbon nanotubes comprise atleast about 70 percent, by weight, of discrete carbon nanotubes.
 21. Thebattery mixture of claim 1, wherein the discrete carbon nanotubes areoxidized.
 22. The battery mixture of claim 4, wherein the discretecarbon nanotubes are oxidized.
 23. The battery mixture of claim 1further comprising an inorganic salt.
 24. The battery mixture of claim 4further comprising an inorganic salt.
 25. The battery mixture of claim 1further comprising a non-fiber carbon moiety.
 26. The battery mixture ofclaim 4 further comprising a non-fiber carbon moiety.